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Characterization of deep-level defects in GaNAs/GaAs heterostructures grown by APMOVPE

Łukasz Gelczuk
Łukasz Gelczuk
, 
Maria Dąbrowska-Szata
Maria Dąbrowska-Szata
, 
Beata Ściana
Beata Ściana
, 
Damian Pucicki
Damian Pucicki
, 
Damian Radziewicz
Damian Radziewicz
, 
Krzysztof Kopalko
Krzysztof Kopalko
 and 
Marek Tłaczała
Marek Tłaczała
   | Dec 19, 2016
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Published Online: Dec 19, 2016
Page range: 726 - 734
Received: Dec 18, 2015
Accepted: Nov 02, 2016
DOI: https://doi.org/10.1515/msp-2016-0126
Keywords
© Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

(a) Current-voltage and (b) capacitance-voltage characteristics recorded at 300 K for all studied samples. In the inset of (b) background doping concentration vs. depth profiles are plotted.
(a) Current-voltage and (b) capacitance-voltage characteristics recorded at 300 K for all studied samples. In the inset of (b) background doping concentration vs. depth profiles are plotted.

Low-temperature DLTS spectra obtained for the GaNxAs1−x/GaAs heterostructures with different nitrogen contents (x) at a reverse bias voltage (VR) of −2 V, a filling pulse voltage (VP) of 0 V, an emission rate window (en) of 20 s−1, and a filling pulse width (tp) of 50 s.
Low-temperature DLTS spectra obtained for the GaNxAs1−x/GaAs heterostructures with different nitrogen contents (x) at a reverse bias voltage (VR) of −2 V, a filling pulse voltage (VP) of 0 V, an emission rate window (en) of 20 s−1, and a filling pulse width (tp) of 50 s.

Exemplary Laplace DLTS spectra of the GaN0.016As0.984/GaAs structure, taken at 160 K, 180 K and 210 K for similar experimental conditions as those of conventional DLTS.
Exemplary Laplace DLTS spectra of the GaN0.016As0.984/GaAs structure, taken at 160 K, 180 K and 210 K for similar experimental conditions as those of conventional DLTS.

The Arrhenius plots of the peaks E1, E2, E3 depicted in Fig. 2 and Fig. 3 for the GaN0.016As0.984/GaAs structure. Crossed points correspond to conventional DLTS analysis and open points to Laplace DLTS analysis.
The Arrhenius plots of the peaks E1, E2, E3 depicted in Fig. 2 and Fig. 3 for the GaN0.016As0.984/GaAs structure. Crossed points correspond to conventional DLTS analysis and open points to Laplace DLTS analysis.

High-temperature DLTS spectra obtained for the GaNxAs1−x/GaAs heterostructures with different nitrogen contents (x). The inset shows corresponding LDLTS spectra recorded at 370 K.
High-temperature DLTS spectra obtained for the GaNxAs1−x/GaAs heterostructures with different nitrogen contents (x). The inset shows corresponding LDLTS spectra recorded at 370 K.

The Arrhenius plots of the peak E4 for all studied samples. Crossed points correspond to conventional DLTS analysis and open points to Laplace DLTS analysis.
The Arrhenius plots of the peak E4 for all studied samples. Crossed points correspond to conventional DLTS analysis and open points to Laplace DLTS analysis.

Activation energy Ea, apparent capture cross section σa and concentration NT obtained from the conventional DLTS and Laplace DLTS analysis of the trap E4 observed in the GaNxAs1−x/GaAs samples (x = 1.2 % to 2.7 %) in high-temperature spectra (>300 K). In the last column, possible identity of the trap has been proposed.

GaNAs/GaAs samplesE4 (EL2)Possible identity
DLTSLDLTS
NT [cm−3]Ea [eV]σa [cm2]Ea [eV]σa [cm2]
1.2% N2.3 × 10130.812.4 × 10−140.817.7 × 10−14EL2a–c
1.6 % N2.0 × 10130.801.2 × 10−140.803.8 × 10−14
2.7 % N2.6 × 10130.811.9 × 10−140.802.3 × 10−14

Concentration of the electron traps E1, E2 and E3 obtained from DLTS measurements of the GaNxAs1−x/GaAs samples (x = 1.2 % to 2.7 %).

GaNAs/GaAsE1 (N-related)E2 (EL6)E3 (EL3)
NT [cm−3]NT [cm−3]NT [cm−3]
1.2 % N1.3 × 10132.1 × 10131.1 × 1013
1.6 % N1.8 × 10134.5 × 10134.2 × 1013
2.7 % N1.6 × 10137.0 × 10134.5 × 1013

Activation energies (Ea) and apparent capture cross sections (σa) obtained from conventional DLTS and Laplace DLTS analysis of the traps E1, E2 and E3 observed in GaNxAs1−x/GaAs samples (x = 1.2 % to 2.7 %) in low-temperature spectra (<300 K). In the last column, possible identities of the traps have been made on the basis of comparison with activation energies of the defects observed in as-grown GaAs and GaNAs, as reported in the references given below.

Trap label1.2 % NGaNAs/GaAs 1.6 % N2.7 % NPossible identity
DLTSDLTSLDLTSDLTS
Ea [eV]σa [cm2]Ea [eV]σa [cm2]Ea [eV]σa [m2]Ea [eV]σa [cm2]
E10.248.8 × 10−180.212.9 × 10−180.203.4 × 10−180.152.1 × 10−18N-relateda−d
E20.321.7 × 10−160.322.5 × 10−160.306.6 × 10−160.321.6 × 10−16EL6e−g
E30.493.9 × 10−130.493.2 × 10−140.481.5 × 10−140.495.2 × 10−14EL3f−h
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